Bicyclic [4,6,0] hydroxamic acids as HDAC inhibitors

ABSTRACT

The present invention relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with HDAC6, having a Formulae I or Formula II: 
                         
where R, L, X 1 , X 2 , X 3 , X 4 , X 5 , Y 1 , Y 2 , Y 3 , and Y 4  are described herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 15/013,811, filed Feb. 2, 2016, which claims the benefit of priority of U.S. Provisional Application No. 62/110,719, filed Feb. 2, 2015, the contents of each of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with HDACs including cell proliferation diseases (e.g., cancer), neurological and inflammatory diseases. Specifically, this invention is concerned with compounds and compositions inhibiting HDACs, methods of treating diseases associated with HDACs, and methods of synthesizing these compounds.

BACKGROUND OF THE INVENTION

Many members of the HDAC family require zinc (Zn) to function properly. For instance, the isozyme histone deacetylase 6 (HDAC6) is a zinc-dependent histone deacetylase that possesses histone deacetylase activity. Other family members include HDACs 1-5 and 7-11. (De Ruijter et al, Biochem. J. 2003. 370; 737-749).

HDAC6 is known to deacetylate and associate with α-tubulin, cortactin, heat shock protein 90, ß-catenin, glucose-regulated protein 78 kDa, myosin heavy chain 9, heat shock cognate protein 70, and dnaJ homolog subfamily A member 1 (reviewed in Li et al, FEBS J. 2013, 280: 775-93; Zhang et al, Protein Cell. 2015, 6(1): 42-54). Diseases in which HDAC6 inhibition could have a potential benefit include cancer (reviewed in Aldana-Masangkay et al, J. Biomed. Biotechnol. 2011, 875824), specifically: multiple myeloma (Hideshima et al, Proc. Natl. Acad. Sci USA 2005, 102(24):8567-8572); lung cancer (Kamemura et al, Biochem. Biophys. Res. Commun. 2008, 374(1):84-89); ovarian cancer (Bazzaro et al, Clin. Cancer Res. 2008, 14(22):7340-7347); breast cancer (Lee et al, Cancer Res. 2008, 68(18):7561-7569; Park et al, Oncol. Rep. 2011, 25: 1677-81; Rey et al, Eur. J. Cell Biol. 2011, 90: 128-35); prostate cancer (Seidel et al, Biochem Pharmacol. 2015 (15)00714-5); pancreatic cancer (Nawrocki et al, Cancer Res. 2006, 66(7):3773-3781); renal cancer (Cha et al, Clin. Cancer Res. 2009, 15(3): 840-850); hepatocellular cancer (Ding et al, FEBS Lett. 2013, 587:880-6; Kanno et al, Oncol. Rep. 2012, 28: 867-73); lymphomas (Ding et al, Cancer Cell Int. 2014, 14:139; Amengual et al, Clin Cancer Res. 2015, 21(20):4663-75); and leukemias such as acute myeloid leukemia (AML) (Fiskus et al, Blood 2008, 112(7):2896-2905) and acute lymphoblastic leukemia (ALL) (Rodriguez-Gonzalez et al, Blood 2008, 112(11): Abstract 1923)).

Inhibition of HDAC6 may also have a role in cardiovascular disease, including pressure overload, chronic ischemia, and infarction-reperfusion injury (Tannous et al, Circulation 2008, 1 17(24):3070-3078); bacterial infection, including those caused by uropathogenic Escherichia coli (Dhakal and Mulve, J. Biol. Chem. 2008, 284(1):446-454); neurological diseases caused by accumulation of intracellular protein aggregates such as Alzheimer's, Parkinson's and Huntington's disease (reviewed in Simoes-Pires et al, Mol Neurodegener. 2013, 8: 7) or central nervous system trauma caused by tissue injury, oxidative-stress induced neuronal or axomal degeneration (Rivieccio et al, Proc. Natl. Acad. Sci. USA 2009, 106(46):19599-195604); and inflammation and autoimmune diseases through enhanced T cell-mediated immune tolerance at least in part through effects on regulatory T cells, including rheumatoid arthritis, psoriasis, spondylitis arthritis, psoriatic arthritis, multiple sclerosis, lupus, colitis and graft versus host disease (reviewed in Wang et al, Nat. Rev. Drug Disc. 2009 8(12):969-981; Vishwakarma et al, Int Immunopharmacol. 2013, 16:72-8; Kalin et al, J. Med Chem. 2012, 55:639-51); and fibrotic disease, including kidney fibrosis (Choi et al, Vascul Pharmacol. 2015 72:130-140).

Four HDAC inhibitors are currently approved for the treatment of some cancers. These are suberanilohydroxamic acid (Vorinostat; Zolinza®) for the treatment of cutaneous T cell lymphoma and multiple myeloma; Romidepsin (FK228; FR901228; Istodax®) for the treatment of peripheral T cell lymphoma; Panobinostat (LBH-589; Farydak®) for the treatment of multiple myeloma; and belinostat (PXD101; Beleodaq®) for the treatment of peripheral T cell lymphoma. However, these drugs are of limited effectiveness and can give rise to unwanted side effects. Thus there is a need for drugs with an improved safety-efficacy profile.

Given the complex function of HDAC6 and their potential utility in the treatment of proliferative diseases, neurological diseases, and inflammatory diseases, there is a need for HDAC inhibitors (e.g., HDAC6 inhibitors) with good therapeutic properties.

SUMMARY OF THE INVENTION

One aspect of the invention relates to compounds of Formula I:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers and isomers thereof, wherein:

X¹ and X² are each independently CR¹R², NR³, O, C═O, SO₂, S(O) or S;

X³, X⁴ and X⁵ are each independently CR¹R², C═O, S(O) or SO₂;

Y¹ and Y⁴ are each independently N or CR¹;

Y² and Y³ are each independently N or CR¹ when not bonded to —C(O)NHOH and Y² and Y³ are C when bonded to —C(O)NHOH;

L is a bond, —(CR¹R²)_(n)—, —C(O)—, —C(O)O—, —C(O)NR³—, —S(O)₂—, —S(O)₂NR³—, —S(O)—, —S(O)NR³—, —C(O)(CR¹R²)_(n)O—, or —C(O)(CR¹R²)_(n);

R is independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, —C₅-C₁₂spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl, with the proviso that when L is —C(O)— the spiroheterocyclyl is not bound to L via a nitrogen atom;

R¹ and R² are independently, and at each occurrence, —H, R³, R⁴, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆alkyl, —N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)₂R⁵, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, or (CHR⁵)_(n)NR³R⁴, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —OR³, —NHR³, NR³R⁴, —S(O)₂N(R³)₂—, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, or heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O;

or R¹ and R² may combine with the carbon atom to which they are both attached to form a spirocycle, spiroheterocycle, or a spirocycloalkenyl;

or R¹ and R², when on adjacent atoms, can combine to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, or cycloalkenyl;

or R¹ and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl or heterocycloalkyl wherein the bridge between X¹ and X⁴ cannot contain exactly one carbon;

R³ and R⁴ are independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, or —(CHR⁵)_(n)N(C₁₋C₆alkyl)₂, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —O(C₁-C₆)alkyl, —NH(C₁-C₆)alkyl, N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂NHC₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, —S(O)R⁵, —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)R⁵, heterocycle, aryl, or heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O;

R⁵ is independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₃-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl, —OH, halogen, —NO₂, —CN, —NHC₁-C₆alkyl, —N(C₁-C₆alkyl)₂, —S(O)₂NH(C₁-C₆alkyl), —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂C₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)SO₂C₁-C₆alkyl, —S(O)(C₁-C₆alkyl), —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)(C₁-C₆alkyl) or (CH₂)_(n)N(C₁-C₆alkyl)₂; and

n is independently, and at each occurrence, an integer from 0 to 6;

provided that X¹, X², X³, X⁴ and X⁵ are not all CR¹R² at the same time.

Another aspect of the invention relates to compounds of Formula II:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers and isomers thereof, wherein:

X¹ is independently CR¹R², NR³, O, C═O, SO₂, S(O) or S;

X², X³, X⁴ and X⁵ are each independently CR¹R², C═O, S(O) or SO₂;

Y¹ and Y⁴ are each independently N or CR¹;

Y² and Y³ are each independently N or CR¹ when not bonded to —C(O)NHOH and Y² and Y³ are C when bonded to —C(O)NHOH;

L is a bond, —(CR¹R²)_(n)—, —C(O)—, —C(O)O—, —C(O)NR³—, —S(O)₂—, —S(O)₂NR³—, —S(O)—, —S(O)NR³—, —C(O)(CR¹R²)_(n)O—, or —C(O)(CR¹R²)_(n);

R is independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, —C₅-C₁₂spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, or —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl, with the proviso that when L is —C(O)— the spiroheterocyclyl is not bound to L via a nitrogen atom;

R¹ and R² are independently, and at each occurrence, —H, R³, R⁴, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆alkyl, —N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)₂R⁵, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, or (CHR⁵)_(n)NR³R⁴, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —OR³, —NHR³, NR³R⁴, —S(O)₂N(R³)₂—, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, or heteroaryl;

or R¹ and R² may combine with the carbon atom to which they are both attached to form a spirocycle, spiroheterocycle, or a spirocycloalkenyl;

or R¹ and R², when on adjacent atoms, can combine to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, or cycloalkenyl;

or R¹ and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl or heterocycloalkyl;

R³ and R⁴ are independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, or —(CHR⁵)_(n)N(C₁-C₆alkyl)₂, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —O(C₁-C₆)alkyl, —NH(C₁-C₆)alkyl, N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂NHC₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, —S(O)R⁵, —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)R⁵, heterocycle, aryl, or heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, or O;

R⁵ is independently, and at each occurrence, —H, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₃-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl, —OH, halogen, —NO₂, —CN, —NHC₁-C₆alkyl, —N(C₁-C₆alkyl)₂, —S(O)₂NH(C₁-C₆alkyl), —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂C₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)SO₂C₁-C₆alkyl, —S(O)(C₁-C₆alkyl), —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)(C₁-C₆alkyl) or (CH₂)_(n)N(C₁-C₆alkyl)₂; and

n is independently and at each occurrence an integer from 0 to 6;

provided that X¹, X², X³, X⁴ and X⁵ are not all CR¹R² at the same time.

Another aspect of the invention relates to a method of treating a disease or disorder associated with HDAC6 modulation in a subject in need thereof, comprising administering to the subject an effective amount of a compound of Formulae I or II.

Another aspect of the invention is directed to a method of inhibiting HDAC6. The method involves administering to a patient in need thereof an effective amount of a compound of Formulae I or II.

Another aspect of the invention is directed to pharmaceutical compositions comprising a compound of Formulae I or II and a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can further include an excipient, diluent, or surfactant. The pharmaceutical composition can be effective for treating a disease or disorder associated with HDAC6 modulation in a subject in need thereof. The pharmaceutical compositions can comprise the compounds of the present invention for use in treating diseases described herein. The compositions can contain at least one compound of the invention and a pharmaceutically acceptable carrier. The invention also provides the use of the compounds described herein in the manufacture of a medicament for the treatment of a disease associated with HDACs.

The present invention also provides methods for the treatment of human diseases or disorders including, without limitation, oncological, neurological, inflammatory, autoimmune, infectious, metabolic, hematologic, or cardiovascular diseases or disorders.

The present invention also provides compounds that are useful in inhibiting of zinc-dependent HDAC enzymes, and in particular HDAC6. These compounds can also be useful in the treatment of diseases including cancer.

The present invention further provides compounds that can inhibit HDAC6. In some embodiments, the efficacy-safety profile of the compounds of the current invention can be improved relative to other known HDAC (e.g. HDAC6) inhibitors. Additionally, the present technology also has the advantage of being able to be used for a number of different types of diseases, including cancer and non-cancer indications. Additional features and advantages of the present technology will be apparent to one of skill in the art upon reading the Detailed Description of the Invention, below.

DETAILED DESCRIPTION OF THE INVENTION

HDAC6 is a zinc-dependent histone deacetylase that has two catalytic domains. HDAC6 can interact with and deacetylate non-histone proteins, including HSP90 and α-tubulin. Acetylation of HSP90 is associated with loss of function of HSP90. HDAC6 is also implicated in the degradation of misfolded proteins as part of the aggresome. Accordingly, inhibition of HDAC6 can have downstream effects that can play a role in the development of certain diseases such as cancer. The present invention provides inhibitors of HDAC6 and methods for using the same to treat disease.

In a first aspect of the invention, compounds of the Formulae I or II are described:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers, and isomers thereof, wherein R, L, X¹, X², X³, X⁴, X⁵, Y¹, Y², Y³, and Y⁴ are described as above.

In a second aspect of the invention, compounds of the Formula II are described:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers, and isomers thereof, wherein R, L, X¹, X², X³, X⁴, X⁵, Y¹, Y², Y³, and Y⁴ are described as above.

The details of the invention are set forth in the accompanying description below. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, illustrative methods and materials are now described. Other features, objects, and advantages of the invention will be apparent from the description and from the claims. In the specification and the appended claims, the singular forms also include the plural unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents and publications cited in this specification are incorporated herein by reference in their entireties.

Definitions

The articles “a” and “an” are used in this disclosure to refer to one or more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

The term “and/or” is used in this disclosure to mean either “and” or “or” unless indicated otherwise.

The term “optionally substituted” is understood to mean that a given chemical moiety (e.g. an alkyl group) can (but is not required to) be bonded other substituents (e.g. heteroatoms). For instance, an alkyl group that is optionally substituted can be a fully saturated alkyl chain (i.e. a pure hydrocarbon). Alternatively, the same optionally substituted alkyl group can have substituents different from hydrogen. For instance, it can, at any point along the chain be bounded to a halogen atom, a hydroxyl group, or any other substituent described herein. Thus the term “optionally substituted” means that a given chemical moiety has the potential to contain other functional groups, but does not necessarily have any further functional groups.

The term “aryl” refers to cyclic, aromatic hydrocarbon groups that have 1 to 2 aromatic rings, including monocyclic or bicyclic groups such as phenyl, biphenyl or naphthyl. Where containing two aromatic rings (bicyclic, etc.), the aromatic rings of the aryl group may be joined at a single point (e.g., biphenyl), or fused (e.g., naphthyl). The aryl group may be optionally substituted by one or more substituents, e.g., 1 to 5 substituents, at any point of attachment. Exemplary substituents include, but are not limited to, —H, -halogen, —O—C₁-C₆alkyl, —C₁-C₆alkyl, —OC₂-C₆alkenyl, —OC₂-C₆alkynyl, —C₂-C₆alkenyl, —C₂-C₆alkynyl, —OH, —OP(O)(OH)₂, —OC(O)C₁-C₆alkyl, —C(O)C₁-C₆alkyl, —OC(O)OC₁-C₆alkyl, —NH₂, —NH(C₁-C₆alkyl), —N(C₁-C₆alkyl)₂, —S(O)₂—C₁-C₆alkyl, —S(O)NHC₁-C₆alkyl, and —S(O)N(C₁-C₆alkyl)₂. The substituents can themselves be optionally substituted. Furthermore when containing two fused rings the aryl groups herein defined may have an unsaturated or partially saturated ring fused with a fully saturated ring. Exemplary ring systems of these aryl groups include indanyl, indenyl, tetrahydronaphthalenyl, and tetrahydrobenzoannulenyl.

Unless otherwise specifically defined, “heteroaryl” means a monovalent monocyclic aromatic radical of 5 to 24 ring atoms or a polycyclic aromatic radical, containing one or more ring heteroatoms selected from N, S, P, or O, the remaining ring atoms being C. Heteroaryl as herein defined also means a bicyclic heteroaromatic group wherein the heteroatom is selected from N, S, P, or O. The aromatic radical is optionally substituted independently with one or more substituents described herein. Examples include, but are not limited to, furyl, thienyl, pyrrolyl, pyridyl, pyrazolyl, pyrimidinyl, imidazolyl, isoxazolyl, oxazolyl, oxadiazolyl, pyrazinyl, indolyl, thiophen-2-yl, quinolyl, benzopyranyl, isothiazolyl, thiazolyl, thiadiazole, indazole, benzimidazolyl, thieno[3,2-b]thiophene, triazolyl, triazinyl, imidazo[1,2-b]pyrazolyl, furo[2,3-c]pyridinyl, imidazo[1,2-a]pyridinyl, indazolyl, pyrrolo[2,3-c]pyridinyl, pyrrolo[3,2-c]pyridinyl, pyrazolo[3,4-c]pyridinyl, thieno[3,2-c]pyridinyl, thieno[2,3-c]pyridinyl, thieno[2,3-b]pyridinyl, benzothiazolyl, indolyl, indolinyl, indolinonyl, dihydrobenzothiophenyl, dihydrobenzofuranyl, benzofuran, chromanyl, thiochromanyl, tetrahydroquinolinyl, dihydrobenzothiazine, dihydrobenzoxanyl, quinolinyl, isoquinolinyl, 1,6-naphthyridinyl, benzo[de]isoquinolinyl, pyrido[4,3-b][1,6]naphthyridinyl, thieno[2,3-b]pyrazinyl, quinazolinyl, tetrazolo[1,5-a]pyridinyl, [1,2,4]triazolo[4,3-a]pyridinyl, isoindolyl, pyrrolo[2,3-b]pyridinyl, pyrrolo[3,4-b]pyridinyl, pyrrolo[3,2-b]pyridinyl, imidazo[5,4-b]pyridinyl, pyrrolo[1,2-a]pyrimidinyl, tetrahydro pyrrolo[1,2-a]pyrimidinyl, 3,4-dihydro-2H-1 X²-pyrrolo[2,1-b]pyrimidine, dibenzo[b,d]thiophene, pyridin-2-one, furo[3,2-c]pyridinyl, furo[2,3-c]pyridinyl, 1H-pyrido[3,4-b][1,4]thiazinyl, benzooxazolyl, benzoisoxazolyl, furo[2,3-b]pyridinyl, benzothiophenyl, 1,5-naphthyridinyl, furo[3,2-b]pyridine, [1,2,4]triazolo[1,5-a]pyridinyl, benzo [1,2,3]triazolyl, imidazo[1,2-a]pyrimidinyl, [1,2,4]triazolo[4,3-b]pyridazinyl, benzo[c][1,2,5]thiadiazolyl, benzo[c][1,2,5]oxadiazole, 1,3-dihydro-2H-benzo[d]imidazol-2-one, 3,4-dihydro-2H-pyrazolo [1,5-b][1,2]oxazinyl, 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridinyl, thiazolo[5,4-d]thiazolyl, imidazo[2,1-b][1,3,4]thiadiazolyl, thieno[2,3-b]pyrrolyl, 3H-indolyl, and derivatives thereof. Furthermore when containing two fused rings the heteroaryl groups herein defined may have an unsaturated or partially saturated ring fused with a fully saturated ring. Exemplary ring systems of these heteroaryl groups include indolinyl, indolinonyl, dihydrobenzothiophenyl, dihydrobenzofuran, chromanyl, thiochromanyl, tetrahydroquinolinyl, dihydrobenzothiazine, 3,4-dihydro-1H-isoquinolinyl, 2,3-dihydrobenzofuran, indolinyl, indolyl, and dihydrobenzoxanyl.

“Alkyl” refers to a straight or branched chain saturated hydrocarbon. C₁-C₆alkyl groups contain 1 to 6 carbon atoms. Examples of a C₁-C₆alkyl group include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, sec-butyl and tert-butyl, isopentyl and neopentyl.

The term “alkenyl” means an aliphatic hydrocarbon group containing a carbon-carbon double bond and which may be straight or branched having about 2 to about 6 carbon atoms in the chain. Preferred alkenyl groups have 2 to about 4 carbon atoms in the chain. Branched means that one or more lower alkyl groups such as methyl, ethyl, or propyl are attached to a linear alkenyl chain. Exemplary alkenyl groups include ethenyl, propenyl, n-butenyl, and i-butenyl. A C₂-C₆ alkenyl group is an alkenyl group containing between 2 and 6 carbon atoms.

The term “alkynyl” means an aliphatic hydrocarbon group containing a carbon-carbon triple bond and which may be straight or branched having about 2 to about 6 carbon atoms in the chain. Preferred alkynyl groups have 2 to about 4 carbon atoms in the chain. Branched means that one or more lower alkyl groups such as methyl, ethyl, or propyl are attached to a linear alkynyl chain. Exemplary alkynyl groups include ethynyl, propynyl, n-butynyl, 2-butynyl, 3-methylbutynyl, and n-pentynyl. A C₂-C₆ alkynyl group is an alkynyl group containing between 2 and 6 carbon atoms.

The term “cycloalkyl” means monocyclic or polycyclic saturated carbon rings containing 3-18 carbon atoms. Examples of cycloalkyl groups include, without limitations, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptanyl, cyclooctanyl, norboranyl, norborenyl, bicyclo[2.2.2]octanyl, or bicyclo[2.2.2]octenyl. A C₃-C₈ cycloalkyl is a cycloalkyl group containing between 3 and 8 carbon atoms. A cycloalkyl group can be fused (e.g., decalin) or bridged (e.g., norbornane).

The term “cycloalkenyl” means monocyclic, non-aromatic unsaturated carbon rings containing 3-18 carbon atoms. Examples of cycloalkenyl groups include, without limitation, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, and norborenyl. A C₃-C₈ cycloalkenyl is a cycloalkenyl group containing between 3 and 8 carbon atoms.

The terms “heterocyclyl” or “heterocycloalkyl” or “heterocycle” refer to monocyclic or polycyclic 3 to 24-membered rings containing carbon and heteroatoms taken from oxygen, nitrogen, or sulfur and wherein there is not delocalized π electrons (aromaticity) shared among the ring carbon or heteroatoms. Heterocyclyl rings include, but are not limited to, oxetanyl, azetadinyl, tetrahydrofuranyl, pyrrolidinyl, oxazolinyl, oxazolidinyl, thiazolinyl, thiazolidinyl, pyranyl, thiopyranyl, tetrahydropyranyl, dioxalinyl, piperidinyl, morpholinyl, thiomorpholinyl, thiomorpholinyl S-oxide, thiomorpholinyl S-dioxide, piperazinyl, azepinyl, oxepinyl, diazepinyl, tropanyl, and homotropanyl. A heteroycyclyl or heterocycloalkyl ring can also be fused or bridged, e.g., can be a bicyclic ring.

As used herein, the term “halo” or “halogen” means fluoro, chloro, bromo, or iodo.

The term “carbonyl” refers to a functional group composing a carbon atom double-bonded to an oxygen atom. It can be abbreviated herein as “oxo”, as C(O), or as C═O.

“Spirocycle” or “spirocyclic” means carbogenic bicyclic ring systems with both rings connected through a single atom. The ring can be different in size and nature, or identical in size and nature. Examples include spiropentane, spriohexane, spiroheptane, spirooctane, spirononane, or spirodecane. One or both of the rings in a spirocycle can be fused to another ring carbocyclic, heterocyclic, aromatic, or heteroaromatic ring. One or more of the carbon atoms in the spirocycle can be substituted with a heteroatom (e.g., O, N, S, or P). A C₃-C₁₂ spirocycle is a spirocycle containing between 3 and 12 carbon atoms. One or more of the carbon atoms can be substituted with a heteroatom.

The term “spirocyclic heterocycle” or “spiroheterocycle” is understood to mean a spirocycle wherein at least one of the rings is a heterocycle (e.g., at least one of the rings is furanyl, morpholinyl, or piperadinyl).

The disclosure also includes pharmaceutical compositions comprising an effective amount of a disclosed compound and a pharmaceutically acceptable carrier. Representative “pharmaceutically acceptable salts” include, e.g., water-soluble and water-insoluble salts, such as the acetate, amsonate (4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzonate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium, calcium edetate, camsylate, carbonate, chloride, citrate, clavulariate, dihydrochloride, edetate, edisylate, estolate, esylate, fiunarate, gluceptate, gluconate, glutamate, glycollylarsanilate, hexafluorophosphate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, sethionate, lactate, lactobionate, laurate, magnesium, malate, maleate, mandelate, mesylate, methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate, oxalate, palmitate, pamoate (1,1-methene-bis-2-hydroxy-3-naphthoate, einbonate), pantothenate, phosphate/diphosphate, picrate, polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate, subacetate, succinate, sulfate, sulfosalicylate, suramate, tannate, tartrate, teoclate, tosylate, triethiodide, and valerate salts.

The term “stereoisomers” refers to the set of compounds which have the same number and type of atoms and share the same bond connectivity between those atoms, but differ in three dimensional structure. The term “stereoisomer” refers to any member of this set of compounds.

The term “diastereomers” refers to the set of stereoisomers which cannot be made superimposable by rotation around single bonds. For example, cis- and trans-double bonds, endo- and exo-substitution on bicyclic ring systems, and compounds containing multiple stereogenic centers with different relative configurations are considered to be diastereomers. The term “diastereomer” refers to any member of this set of compounds. In some examples presented, the synthetic route may produce a single diastereomer or a mixture of diastereomers. In some cases these diastereomers were separated and in other cases a wavy bond is used to indicate the structural element where configuration is variable.

The term “enantiomers” refers to a pair of stereoisomers which are non-superimposable mirror images of one another. The term “enantiomer” refers to a single member of this pair of stereoisomers. The term “racemic” refers to a 1:1 mixture of a pair of enantiomers.

The term “tautomers” refers to a set of compounds that have the same number and type of atoms, but differ in bond connectivity and are in equilibrium with one another. A “tautomer” is a single member of this set of compounds. Typically a single tautomer is drawn but it is understood that this single structure is meant to represent all possible tautomers that might exist. Examples include enol-ketone tautomerism. When a ketone is drawn it is understood that both the enol and ketone forms are part of the invention.

An “effective amount” when used in connection with a compound is an amount effective for treating or preventing a disease in a subject as described herein.

The term “carrier”, as used in this disclosure, encompasses carriers, excipients, and diluents and means a material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting a pharmaceutical agent from one organ, or portion of the body, to another organ, or portion of the body of a subject.

The term “treating” with regard to a subject, refers to improving at least one symptom of the subject's disorder. Treating includes curing, improving, or at least partially ameliorating the disorder.

The term “disorder” is used in this disclosure to mean, and is used interchangeably with, the terms disease, condition, or illness, unless otherwise indicated.

The term “administer”, “administering”, or “administration” as used in this disclosure refers to either directly administering a disclosed compound or pharmaceutically acceptable salt of the disclosed compound or a composition to a subject, or administering a prodrug derivative or analog of the compound or pharmaceutically acceptable salt of the compound or composition to the subject, which can form an equivalent amount of active compound within the subject's body.

The term “prodrug,” as used in this disclosure, means a compound which is convertible in vivo by metabolic means (e.g., by hydrolysis) to a disclosed compound. Furthermore, as used herein a prodrug is a drug which is inactive in the body, but is transformed in the body typically either during absorption or after absorption from the gastrointestinal tract into the active compound. The conversion of the prodrug into the active compound in the body may be done chemically or biologically (i.e., using an enzyme).

The term “solvate” refers to a complex of variable stoichiometry formed by a solute and solvent. Such solvents for the purpose of the invention may not interfere with the biological activity of the solute. Examples of suitable solvents include, but are not limited to, water, MeOH, EtOH, and AcOH. Solvates wherein water is the solvent molecule are typically referred to as hydrates. Hydrates include compositions containing stoichiometric amounts of water, as well as compositions containing variable amounts of water.

The term “isomer” refers to compounds that have the same composition and molecular weight but differ in physical and/or chemical properties. The structural difference may be in constitution (geometric isomers) or in the ability to rotate the plane of polarized light (stereoisomers). With regard to stereoisomers, the compounds of Formulae I or II may have one or more asymmetric carbon atom and may occur as racemates, racemic mixtures and as individual enantiomers or diastereomers.

A “patient” or “subject” is a mammal, e.g., a human, mouse, rat, guinea pig, dog, cat, horse, cow, pig, or non-human primate, such as a monkey, chimpanzee, baboon or rhesus.

In one embodiment of the compounds of Formula I, X⁵ is CR¹R².

In another embodiment of the compounds of Formula I, X¹ is NR³, O, C═O, SO₂, or S.

In another embodiment of the compounds of Formula I, X¹ is O and X⁵ is CR¹R².

In another embodiment of the compounds of Formula I, L is CH₂.

In another embodiment of the compounds of Formula I, L is —C(O)—.

In another embodiment of the compounds of Formula I, any two or more of R¹ and R² may combine with the carbon atom or atoms to which they are attached to form a heterocycle, a cycloalkyl, or a spirocycle only when X¹ is O, S, or N.

In another embodiment of the compounds of Formula I, any two or more of R¹ and R², when on adjacent atoms, may attach to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1-5 heteroatoms, or cycloalkenyl only when X¹ is O, S, or N.

In another embodiment of the compounds of Formula I, any two or more of R¹, and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl or heterocycloalkyl only when X¹ is O, S, or N.

In one embodiment of the compounds of Formula II, X⁵ is CR¹R².

In another embodiment of the compounds of Formula II, X¹ is NR³, O, C═O, SO₂, or S.

In another embodiment of the compounds of Formula II, X¹ is O and X⁵ is CR¹R².

In another embodiment of the compounds of Formula II, L is CH₂.

In another embodiment of the compounds of Formula II, L is —C(O)—.

In another embodiment of the compounds of Formula II, any two or more of R¹, and R² may combine with the carbon atom or atoms to which they are attached to form a heterocycle, a cycloalkyl, or a spirocycle only when X¹ is O, S, or N; or two or more of R¹ and R² when on adjacent atoms, may attach to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1-5 heteroatoms, or cycloalkenyl only when X¹ is O, S, or N; or two or more of R¹ and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl or heterocycloalkyl only when X¹ is O, S, or N.

In one embodiment, when X² and X⁵ are both C═O, X¹ is not NR⁵.

In one embodiment of the compounds of Formula I are described compounds of the Formula IA:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers or isomer thereof; where R, L, X¹, X², X³, X⁴, X⁵, Y¹, Y³, and Y⁴ are defined as above in Formula I.

In some embodiments of the invention, the compounds of Formula IA may be of the formula IA-1:

In other embodiments of the compounds of Formula IA, the compound is of the formula IA-2:

In yet other another embodiments of the compounds of Formula IA, the compound is of the formula IA-3:

In one embodiment of the compounds of Formula I are also disclosed compounds of the Formula IB:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, enantiomers and isomers thereof where R, L, X¹, X², X³, X⁴, X⁵, Y¹, Y², and Y⁴ are defined as above in Formula I.

In one embodiment of the compounds of Formula II are described compounds of the Formula IIA:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers or isomer thereof; where R, L, X¹, X², X³, X⁴, X⁵, Y¹, Y³, and Y⁴ are defined as above in Formula II.

In other embodiments of the compounds of Formula IIA, the compound is of the formula IIA-1:

In yet other embodiments of the compounds of Formula IIA, the compound is of the formula (IIA-2):

In other embodiments of the compounds of Formula II, the compound may also be of the formula II-B:

In some embodiments of Formula (I), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR¹R². In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², and X⁵ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is a bond. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂NR³—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)NR³—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)O—. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)_(n)—.

In some embodiments of Formula (II), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR¹R². In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², and X⁵ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is a bond. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂NR³—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)NR³—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)O—. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)_(n)—.

In some embodiments of Formula (I), X² is NR³. In another embodiment, X² is NR³ and X¹ is CR¹R². In yet another embodiment, X¹ is CR¹R², X² is NR³, and X³ is CR¹R². In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², and X⁴ is CR¹R². In yet another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², and X⁵ is CR¹R². In yet another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)—. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is a bond. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂—. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —S(O)₂NR³—. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)NR³—. In another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², X⁵ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)O—. In yet another embodiment, X¹ is CR¹R², X² is NR³, X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)n-

In some embodiments of Formulae (I) and (II), R is H, —C₁-C₆ alkyl, —C₄-C₈ cycloalkenyl, —C₃-C₈ cycloalkyl, —C₅-C₁₂ spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each alkyl, cycloalkenyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, or —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, with the proviso that R is not bound to L via a nitrogen atom.

In some embodiments of Formulae (I) and (II), n is 1 to 6. In another embodiment, n is 0 to 5. In yet another embodiment, n is 0 to 4. In yet another embodiment, n is 1 to 4. In another embodiment, n is 0 to 3. In yet another embodiment, n is 0 to 2. In yet another embodiment, n is 0 or 1. In another embodiment, n is 1 or 2.

In some embodiments of Formulae (I) and (II), R¹ and R² may combine with the atom to which they are both attached to form a spirocycle. In another embodiment, R¹ and R² combine with the atom to which they are both attached to form a spiroheterocycle. In another embodiment, R¹ and R² combine with the atom to which they are both attached to form a spirocycloalkenyl.

In some embodiments of Formulae (I) and (II), R¹ and R², when on adjacent atoms, combine to form a heterocycle. In another embodiment, R¹ and R², when on adjacent atoms, combine to form a cycloalkyl. In yet another embodiment, R¹ and R², when on adjacent atoms, combine to form a cycloalkenyl. In another embodiment, R¹ and R², when on adjacent atoms, combine to form an aryl. In yet another embodiment, R¹ and R², when on adjacent atoms, combine to form a heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O.

In some embodiments of Formula (I), R¹ and R², when on non-adjacent atoms, combine to form a bridging cycloalkyl. In another embodiment, R¹ and R², when on non-adjacent atoms, combine to form a bridging cycloalkenyl. In yet another embodiment, R¹ and R², when on non-adjacent atoms, combine to form a heterocycloalkyl.

In an illustrative embodiment, the compound of Formula I is:

-   N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][15]oxazocine-9-carboxamide; -   N-hydroxy-5-(4-methyltetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-phenyl-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   5-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   5-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   5-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-benzo[b][15]oxazocine-9-carboxamide; -   N9-hydroxy-N5-phenyl-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5,9(6H)-dicarboxamide;     N-hydroxy-5-(N-phenyl     sulfamoyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   5-(cyclohexylmethyl)-N-hydroxy-6-oxo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-phenyl-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   5-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   5-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   5-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-9-carboxamide; -   N9-hydroxy-N5-phenyl-3,4-dihydro-2H-2,4-methanobenzo[b][1,5]oxazocine-5,9(6H)-dicarboxamide; -   N-hydroxy-5-(N-phenylsulfamoyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][15]oxazocine-9-carboxamide; -   N-hydroxy-5-methyl-2-phenyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   2-benzyl-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   2-benzoyl-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   2-(cyclohexanecarbonyl)-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   N-hydroxy-5-methyl-2-(tetrahydro-2H-pyran-4-carbonyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   N8-hydroxy-5-methyl-N2-phenyl-3,4,5,6-tetrahydrobenzo[f][1,4]diazocine-2,8(1H)-dicarboxamide; -   N-hydroxy-5-methyl-2-(N-phenylsulfamoyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   N-hydroxy-5-phenyl-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   5-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   5-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   5-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-5-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   N8-hydroxy-N5-phenyl-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5,8(6H)-dicarboxamide; -   N-hydroxy-5-(N-phenylsulfamoyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   5-(cyclohexylmethyl)-N-hydroxy-6-oxo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-5-phenyl-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   5-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   5-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   5-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-5-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   N8-hydroxy-N5-phenyl-3,4-dihydro-2H-2,4-methanobenzo[b][1,5]oxazocine-5,8(6H)-dicarboxamide; -   N-hydroxy-5-(N-phenylsulfamoyl)-3,4,5,6-tetrahydro-2H-2,4-methanobenzo[b][1,5]oxazocine-8-carboxamide; -   N-hydroxy-2-methyl-5-phenyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   5-benzyl-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   5-benzoyl-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   5-(cyclohexanecarbonyl)-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   N-hydroxy-2-methyl-5-(tetrahydro-2H-pyran-4-carbonyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; -   N9-hydroxy-5-methyl-N2-phenyl-3,4,5,6-tetrahydrobenzo[f][1,4]diazocine-2,9(1H)-dicarboxamide;     or -   N-hydroxy-2-methyl-5-(N-phenylsulfamoyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide.

In an illustrative embodiment the compound of Formula II is:

-   N-hydroxy-4-phenyl-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   4-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   4-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   4-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   N-hydroxy-4-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   N-hydroxy-4-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   N9-hydroxy-N4-phenyl-2,3,5,6-tetrahydro-4H-benzo[g][1,4]oxazocine-4,9-dicarboxamide; -   4-(cyclohexylmethyl)-N-hydroxy-5-oxo-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-9-carboxamide; -   N-hydroxy-4-phenyl-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   4-benzyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   4-benzoyl-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   4-(cyclohexanecarbonyl)-N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   N-hydroxy-4-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   N-hydroxy-4-(phenylsulfonyl)-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide; -   N8-hydroxy-N4-phenyl-2,3,5,6-tetrahydro-4H-benzo[g][1,4]oxazocine-4,8-dicarboxamide;     or -   4-(cyclohexylmethyl)-N-hydroxy-5-oxo-3,4,5,6-tetrahydro-2H-benzo[g][1,4]oxazocine-8-carboxamide.

In another embodiment, illustrative compounds of the invention include:

-   N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide; -   N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide;     and -   N-hydroxy-5-(4-methyltetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide.

In another embodiment of the invention, the compounds of Formulae I or II are enantiomers. In some embodiments the compounds are the (S)-enantiomer. In other embodiments the compounds are the (R)-enantiomer. In yet other embodiments, the compounds of Formulae I or II may be (+) or (−) enantiomers.

It should be understood that all isomeric forms are included within the present invention, including mixtures thereof. If the compound contains a double bond, the substituent may be in the E or Z configuration. If the compound contains a disubstituted cycloalkyl, the cycloalkyl substituent may have a cis- or trans configuration. All tautomeric forms are also intended to be included.

Methods of Synthesizing the Disclosed Compounds

The compounds of the present invention may be made by a variety of methods, including standard chemistry. Suitable synthetic routes are depicted in the schemes given below.

The compounds of Formulae I or II may be prepared by methods known in the art of organic synthesis as set forth in part by the following synthetic schemes and examples. In the schemes described below, it is well understood that protecting groups for sensitive or reactive groups are employed where necessary in accordance with general principles or chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis”, Third edition, Wiley, New York 1999). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection processes, as well as the reaction conditions and order of their execution, shall be consistent with the preparation of compounds of Formulae I or II.

Those skilled in the art will recognize if a stereocenter exists in the compounds of Formulae I or II. Accordingly, the present invention includes both possible stereoisomers (unless specified in the synthesis) and includes not only racemic compounds but the individual enantiomers and/or diastereomers as well. When a compound is desired as a single enantiomer or diastereomer, it may be obtained by stereospecific synthesis or by resolution of the final product or any convenient intermediate. Resolution of the final product, an intermediate, or a starting material may be affected by any suitable method known in the art. See, for example, “Stereochemistry of Organic Compounds” by E. L. Eliel, S. H. Wilen, and L. N. Mander (Wiley-lnterscience, 1994).

The compounds described herein may be made from commercially available starting materials or synthesized using known organic, inorganic, and/or enzymatic processes.

Preparation of Compounds

The compounds of the present invention can be prepared in a number of ways well known to those skilled in the art of organic synthesis. By way of example, compounds of the present invention can be synthesized using the methods described below, together with synthetic methods known in the art of synthetic organic chemistry, or variations thereon as appreciated by those skilled in the art. These methods include but are not limited to those methods described below. Compounds of the present disclosure can be synthesized by following the steps outlined in General Schemes 1, 2, and 3 which comprise different sequences of assembling intermediates 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m, 2n, 2o, 2p, 2q, 2r, 2s, 2t, and 2u. Starting materials are either commercially available or made by known procedures in the reported literature or as illustrated.

The general way of preparing target molecules of Formula (I) by using intermediates 2a, 2b, 2c, 2d, 2e, 2f, 2g, and 2h is outlined in General Scheme 1. Esterification of Intermediate 2a in an alcohol, e.g., methanol (MeOH) in the presence of an acid, e.g., sulfuric acid (H₂SO₄) provides Intermediate 2b. Nucleophilc addition of alcohol 2b to intermediate 2c using a base, e.g., potassium carbonate (K₂CO₃) in a solvent, e.g., acetone, provides Intermediate 2d. Deprotection of 2d with an acid, e.g., trifluoroacetic acid (TFA) in a solvent, e.g., dichloromethane, and subsequent cyclization in the presence of a base, e.g., LiHMDS provides intermediate 2e. Reduction of the amide linkage in 2e with a mild reducing agent, for instance, borane, in the presence of a solvent, e.g., tetrahydrofuran (THF) provides Intermediate 2f. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, acylation, sulfonation, or coupling reactions. For example, coupling of a carboxylic acid with Intermediate 2f under standard coupling conditions using a coupling reagent, e.g., 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxide hexafluorophosphate (HATU), or O-benzotriazole-N,N,N′,N′-tetramethyl-uronium-hexafluoro-phosphate (HBTU), and a base, e.g., triethylamine or N,N-diisopropylethylamine (DIPEA), in a solvent, e.g., DMF, provides Intermediate 2g. The coupled product 2g can be carbonylated in the presence of a metal catalyst, e.g., [1,1′-bis(diphenylphosphino)ferrocene]dichloro palladium(II) and carbon monoxide in a solvent, e.g., ethanol to provide Intermediate 2h. Treatment of intermediate 2h with hydroxylamine and a base, e.g., aqueous sodium hydroxide (NaOH (aq)) in a solvent, e.g., tetrahydrofuran and/or methanol provides compounds of Formula (I).

The general way of preparing target molecules of Formula (I) by using Intermediates 2b, 2i, 2j, 2k, 2m, 2n, and 2o is outlined in General Scheme 2. A secondary alcohol such as that of 2i is activated in the presence of, for instance, diethyl azodicarboxylate (DEAD) and triphenylphosphine (PPh₃) and in a solvent, e.g., tetrahydrofuran (THF) and reacted with the hydroxy group of Intermediate 2b to give Intermediate 2j. Reduction of the ester in 2j with a reducing agent, e.g., lithium aluminum hydride (LAH) in a solvent, e.g., tetrahydrofuran (THF) provides the corresponding alcohol which is converted to a primary benzyl chloride 2k by treating with thionyl chloride (SOCl₂) in a solvent, e.g., dichloromethane (DCM). An intramolecular nucleophilic substitution reaction in the presence of a base, e.g., potassium carbonate (K₂CO₃) in a solvent, e.g., dimethylformamide (DMF) provides intermediate 2m. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, acylation, sulfonation, or coupling reactions. For example, coupling of a carboxylic acid with Intermediate 2m under standard coupling conditions using a coupling reagent, e.g., 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxide hexafluoro-phosphate (HATU), or O-benzotriazole-N,N,N′,N′-tetramethyl-uronium-hexafluoro-phosphate (HBTU), and a base, e.g., triethylamine or N,N-diisopropylethylamine (DIPEA), in a solvent, e.g., DMF, provides Intermediate 2n. The coupled product 2n can be carbonylated in the presence of a metal catalyst, e.g., [1,1′-bis(diphenylphosphino)ferrocene]dichloro palladium(II) and carbon monoxide in a solvent, e.g., methanol to provide Intermediate 2o. Treatment of intermediate 2o with hydroxylamine and a base, e.g., aqueous sodium hydroxide (NaOH (aq)) in a solvent, e.g., tetrahydrofuran and/or methanol provides compounds of Formula (I).

The general way of preparing target molecules of Formula (I) by using Intermediates 2p, 2q, 2r, 2s, 2t, and 2u is outlined in General Scheme 3. Reductive amination of the aldehyde of 2q with the amino group of 2p in the presence of an acid, e.g., acetic acid using a reducing agent, e.g., sodium cyanoborohydride (NaBH₃CN) in a solvent, e.g., dichloromethane (DCM) followed by protection of the resulting amine with a protecting group, e.g., benzyl chloroformate, in the presence of a base, e.g., potassium carbonate (K₂CO₃), provides Intermediate 2r. Selective depotection of the tert-butoxycarbonyl (Boc) protecting group of 2r in the presence of an acid, e.g., trifluoroacetic acid (TFA), in a solvent, e.g., dichloromethane (DCM) followed by treatment with a base, e.g., potassium carbonate (K₂CO₃), completes an intramolecular nucleophilc substitution reaction to form a bicycle. Deprotection of the carboxybenzyl protecting group under an atmosphere of hydrogen with catalytic palladium on carbon affords Intermediate 2s. The deprotected product 2s can be carbonylated in the presence of a metal catalyst, e.g., [1,1′-bis(diphenylphosphino)ferrocene]dichloro palladium(II)-dichloromethane adduct and carbon monoxide in a solvent, e.g., methanol to provide Intermediate 2t. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, acylation, sulfonation, or coupling reactions. For example, coupling of a carboxylic acid with Intermediate 2t under standard coupling conditions using a coupling reagent, e.g., 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxide hexafluoro-phosphate (HATU), or O-benzotriazole-N,N,N′,N′-tetramethyl-uronium-hexafluoro-phosphate (HBTU), and a base, e.g., triethylamine or N,N-diisopropylethylamine (DIPEA), in a solvent, e.g., DMF, provides Intermediate 2u. Treatment of intermediate 2u with hydroxylamine and a base, e.g., aqueous sodium hydroxide (NaOH (aq)) in a solvent, e.g., tetrahydrofuran and/or methanol provides compounds of Formula (I).

Methods of Using the Disclosed Compounds

Another aspect of the invention relates to a method of treating a disease associated with HDAC, e.g., HDAC6, modulation in a subject in need thereof. The method involves administering to a patient in need of treatment for diseases or disorders associated with HDAC, e.g., HDAC6, modulation an effective amount of a compound of Formula I. In an embodiment, the disease can be, but is not limited to, cancer, neurodegenerative disease, neurodevelopmental disease, inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease.

Another aspect of the invention is directed to a method of inhibiting an HDAC, e.g., HDAC6. The method involves administering to a patient in need thereof an effective amount of Formula I.

The present invention relates to compositions capable of modulating the activity of (e.g., inhibiting) HDACs, for instance HDAC6. The present invention also relates to the therapeutic use of such compounds.

One therapeutic use of the compounds of the present invention is to treat proliferative diseases or disorders such as cancer. Cancer can be understood as abnormal or unregulated cell growth within a patient and can include but is not limited to lung cancer, ovarian cancer, breast cancer, prostate cancer, pancreatic cancer, hepatocellular cancer, renal cancer and leukemias such as acute myeloid leukemia and acute lymphoblastic leukemia. Additional cancer types include T-cell lymphoma (e.g., cutaneous T-cell lymphoma, peripheral T-cell lymphoma), and multiple myeloma.

One therapeutic use of the compounds of the present invention is to treat neurological diseases or disorders or neurodegeneration. Neurological disorders are understood as disorders of the nervous system (e.g., the brain and spinal cord). Neurological disorders or neurodegenerative diseases can include but are not limited to epilepsy, attention deficit disorder (ADD), Alzheimer's disease, Parkinson's Disease, Huntington's Disease, amyotrophic lateral sclerosis, spinal muscular atrophy, essential tremor, central nervous system trauma caused by tissue injury, oxidative stress-induced neuronal or axomal degeneration, and multiple sclerosis.

Another therapeutic use of the compounds of the present invention is to treat neurodevelopmental disorders. Neurodevelopmental disorders can include, but are not limited to, Rett syndrome.

Another therapeutic use of the compounds of the present invention is also to treat inflammatory diseases or disorders. Inflammation can be understood as a host's response to an initial injury or infection. Symptoms of inflammation can include but are not limited to redness, swelling, pain, heat and loss of function. Inflammation may be caused by the upregulation of pro-inflammatory cytokines such as IL-10, and increased expression of the FOXP3 transcription factor.

Another therapeutic use of the compounds of the present invention is also to treat autoimmune diseases or disorders. Autoimmune disorders are understood as disorders wherein a host's own immune system responds to tissues and substances occurring naturally in the host's body. Autoimmune diseases can include but are not limited to Rheumatoid arthritis, spondylitis arthritis, psoriatic arthritis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, graft versus host disease, transplant rejection, fibrotic disease, Crohn's Disease, type-1 diabetes, Eczema, and psoriasis.

Another therapeutic use of the compounds of the present invention is also to treat infectious diseases or disorders. Infections or infectious diseases are caused by the invasion of a foreign pathogen. The infection may be caused by, for instance, a bacteria, a fungus, or virus. For example, a bacterial infection may be caused by a E. coli.

Yet another therapeutic use of the compounds of the present invention is also to treat metabolic diseases or disorders. Metabolic diseases can be characterized as abnormalities in the way that a subject stores energy. Metabolic disorders can include but are not limited to metabolic syndrome, diabetes, obesity, high blood pressure, and heart failure.

Yet another therapeutic use of the compounds of the present invention is also to treat hematologic disorders. Hematologic diseases primarily affect the blood. Hematologic disorders can include but are not limited to anemia, lymphoma, and leukemia.

Yet another therapeutic use of the compounds of the present invention is also to treat cardiovascular diseases or disorders. Cardiovascular diseases affect the heart and blood vessels of a patient. Exemplary conditions include but are not limited to cardiovascular stress, pressure overload, chronic ischemia, infarction-reperfusion injury, hypertension, atherosclerosis, peripheral artery disease, and heart failure.

The disclosed compound can be administered in effective amounts to treat or prevent a disorder and/or prevent the development thereof in subjects.

Administration of the disclosed compounds can be accomplished via any mode of administration for therapeutic agents. These modes include systemic or local administration such as oral, nasal, parenteral, transdermal, subcutaneous, vaginal, buccal, rectal or topical administration modes.

Depending on the intended mode of administration, the disclosed compositions can be in solid, semi-solid or liquid dosage form, such as, for example, injectables, tablets, suppositories, pills, time-release capsules, elixirs, tinctures, emulsions, syrups, powders, liquids, suspensions, or the like, sometimes in unit dosages and consistent with conventional pharmaceutical practices. Likewise, they can also be administered in intravenous (both bolus and infusion), intraperitoneal, subcutaneous or intramuscular form, all using forms well known to those skilled in the pharmaceutical arts.

Illustrative pharmaceutical compositions are tablets and gelatin capsules comprising a Compound of the Invention and a pharmaceutically acceptable carrier, such as a) a diluent, e.g., purified water, triglyceride oils, such as hydrogenated or partially hydrogenated vegetable oil, or mixtures thereof, corn oil, olive oil, sunflower oil, safflower oil, fish oils, such as EPA or DHA, or their esters or triglycerides or mixtures thereof, omega-3 fatty acids or derivatives thereof, lactose, dextrose, sucrose, mannitol, sorbitol, cellulose, sodium, saccharin, glucose and/or glycine; b) a lubricant, e.g., silica, talcum, stearic acid, its magnesium or calcium salt, sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and/or polyethylene glycol; for tablets also; c) a binder, e.g., magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, magnesium carbonate, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, waxes and/or polyvinylpyrrolidone, if desired; d) a disintegrant, e.g., starches, agar, methyl cellulose, bentonite, xanthan gum, algiic acid or its sodium salt, or effervescent mixtures; e) absorbent, colorant, flavorant and sweetener; f) an emulsifier or dispersing agent, such as Tween 80, Labrasol, HPMC, DOSS, caproyl 909, labrafac, labrafil, peceol, transcutol, capmul MCM, capmul PG-12, captex 355, gelucire, vitamin E TGPS or other acceptable emulsifier; and/or g) an agent that enhances absorption of the compound such as cyclodextrin, hydroxypropyl-cyclodextrin, PEG400, PEG200.

Liquid, particularly injectable, compositions can, for example, be prepared by dissolution, dispersion, etc. For example, the disclosed compound is dissolved in or mixed with a pharmaceutically acceptable solvent such as, for example, water, saline, aqueous dextrose, glycerol, ethanol, and the like, to thereby form an injectable isotonic solution or suspension. Proteins such as albumin, chylomicron particles, or serum proteins can be used to solubilize the disclosed compounds.

The disclosed compounds can be also formulated as a suppository that can be prepared from fatty emulsions or suspensions; using polyalkylene glycols such as propylene glycol, as the carrier.

The disclosed compounds can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, containing cholesterol, stearylamine or phosphatidylcholines. In some embodiments, a film of lipid components is hydrated with an aqueous solution of drug to a form lipid layer encapsulating the drug, as described in U.S. Pat. No. 5,262,564.

Disclosed compounds can also be delivered by the use of monoclonal antibodies as individual carriers to which the disclosed compounds are coupled. The disclosed compounds can also be coupled with soluble polymers as targetable drug carriers. Such polymers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamide-phenol, polyhydroxyethylaspanamidephenol, or polyethyleneoxidepolylysine substituted with palmitoyl residues. Furthermore, the disclosed compounds can be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross-linked or amphipathic block copolymers of hydrogels. In one embodiment, disclosed compounds are not covalently bound to a polymer, e.g., a polycarboxylic acid polymer, or a polyacrylate.

Parental injectable administration is generally used for subcutaneous, intramuscular or intravenous injections and infusions. Injectables can be prepared in conventional forms, either as liquid solutions or suspensions or solid forms suitable for dissolving in liquid prior to injection.

Another aspect of the invention relates to a pharmaceutical composition comprising a compound of Formulae I or II and a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can further include an excipient, diluent, or surfactant.

Compositions can be prepared according to conventional mixing, granulating or coating methods, respectively, and the present pharmaceutical compositions can contain from about 0.1% to about 99%, from about 5% to about 90%, or from about 1% to about 20% of the disclosed compound by weight or volume.

The dosage regimen utilizing the disclosed compound is selected in accordance with a variety of factors including type, species, age, weight, sex and medical condition of the patient; the severity of the condition to be treated; the route of administration; the renal or hepatic function of the patient; and the particular disclosed compound employed. A physician or veterinarian of ordinary skill in the art can readily determine and prescribe the effective amount of the drug required to prevent, counter or arrest the progress of the condition.

Effective dosage amounts of the disclosed compounds, when used for the indicated effects, range from about 0.5 mg to about 5000 mg of the disclosed compound as needed to treat the condition. Compositions for in vivo or in vitro use can contain about 0.5, 5, 20, 50, 75, 100, 150, 250, 500, 750, 1000, 1250, 2500, 3500, or 5000 mg of the disclosed compound, or, in a range of from one amount to another amount in the list of doses. In one embodiment, the compositions are in the form of a tablet that can be scored.

Without wishing to be bound by any particular theory, the compounds of the present invention can inhibit HDACs such as HDAC6 by interacting with the zinc (Zn²⁺) ion in the protein's active site via the hydroxamic acid group bound to the aromatic ring of the compound. The binding can prevent the zinc ion from interacting with its natural substrates, thus inhibiting the enzyme.

Examples

The disclosure is further illustrated by the following examples and synthesis examples, which are not to be construed as limiting this disclosure in scope or spirit to the specific procedures herein described. It is to be understood that the examples are provided to illustrate certain embodiments and that no limitation to the scope of the disclosure is intended thereby. It is to be further understood that resort may be had to various other embodiments, modifications, and equivalents thereof which may suggest themselves to those skilled in the art without departing from the spirit of the present disclosure and/or scope of the appended claims.

The present invention includes a number of unique features and advantages compared with other inhibitors of HDAC enzymes, in particular HDAC6. For instance, the present invention features a unique class of small molecule therapeutic agents of Formulae I or II. The compounds were designed by using crystal structure information of HDAC ligand-protein complexes as well as advanced computational chemistry tools. These techniques led to the development of new chemical scaffolds that were iteratively refined to optimize key recognition features between the ligand and receptor known to be necessary for potency.

Definitions used in the following examples and elsewhere herein are:

-   BH₃: borane -   DMSO: dimethylsulfoxide -   EtOH: ethanol -   H₂SO₄: sulfuric acid -   KCl: potassium chloride -   LiHMDS: lithium bis(trimethylsilyl)amide -   CH2Cl2: methylene chloride, dichloromethane -   CO: carbon monoxide -   DIEA: diisopropylethylamine -   DMF: N,N-dimethylformamide -   EtOAc: ethyl acetate -   H2O: water -   HCl: hydrochloric acid -   HATU:     1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium     3-oxid hexafluorophosphate -   MeCN: acetonitrile -   MeOH: methanol -   NaHCO₃: sodium bicarbonate -   NaOH: sodium hydroxide -   Pd(dppf)Cl₂.CH₂Cl₂: [1,1′-bis(diphenylphosphino)ferrocene]dichloro     palladium(II)-dichloromethane adduct -   pet. ether: petroleum ether -   TFA: trifluoroacetic acid -   THF: tetrahydrofuran

Example 1—Preparation of N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide

Step-1: Methyl 4-bromo-2-hydroxybenzoate

4-Bromo-2-hydroxybenzoic acid (10.0 g, 46.08 mmol, 1.0 equiv) and MeOH (50 mL) were placed in a 250-mL round-bottom flask. This was followed by the addition of sulfuric acid (20 mL) dropwise with stirring at 0° C. The resulting solution was stirred for 16 h at 65° C. in an oil bath, then concentrated under vacuum. The residue was dissolved in EtOAc (300 mL) and washed with H₂O (3×100 mL) and aq. 2N NaHCO₃ (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by silica gel chromatography (EtOAc/pet. ether, 1:20) to afford methyl 4-bromo-2-hydroxybenzoate as a light yellow solid (7.80 g, 73% yield). MS: (ES, m/z): 231 [M+H]+.

Step-2: Methyl 4-bromo-2-(3-(tert-butoxycarbonylamino)propoxy)benzoate

Methyl 4-bromo-2-hydroxybenzoate (3.00 g, 12.98 mmol, 1.0 equiv) in propan-2-one (15 mL), potassium carbonate (5.40 g, 39.07 mmol, 3.0 equiv) and tert-butyl N-(3-bromopropyl)carbamate (3.7 g, 15.54 mmol, 1.20 equiv) were place in a 100-mL round-bottom flask. The resulting mixture was stirred for 16 h at 60° C. in an oil bath, then concentrated under vacuum. The residue was dissolved in EtOAc (200 mL) and washed with H₂O (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to afford methyl 4-bromo-2-(3-(tert-butoxycarbonylamino)propoxy)benzoate as a light yellow oil (5.89 g). This material was used without further purification. MS: (ES, m/z): 388 [M+H]⁺.

Step-3: Methyl 2-(3-aminopropoxy)-4-bromobenzoate

Methyl 4-bromo-2-(3-(tert-butoxycarbonylamino)propoxy)benzoate (3.0 g, 7.73 mmol) and dichloromethane (10 mL) were placed in a 100-mL round-bottom flask. This was followed by the addition of trifluoroacetic acid (10 mL) dropwise with stirring at 0° C. The resulting solution was stirred for 3 h at room temperature, then concentrated under vacuum. The residue was dissolved in H₂O (150 mL) and the pH of the solution was adjusted to 8 with aq. 4N NaOH. The resulting solution was extracted with EtOAc (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford methyl 2-(3-aminopropoxy)-4-bromobenzoate as a yellow oil (1.57 g, 71% yield). MS: (ES, m/z): 288 [M+H]⁺.

Step-4: 9-Bromo-2,3,4,5-tetrahydro-6H-benzo[b][1,5]oxazocin-6-one

Methyl 2-(3-aminopropoxy)-4-bromobenzoate (1.57 g, 5.45 mmol, 1.0 equiv) and THF (1.5 L) were placed in a 3-L 3-necked round-bottom flask that has been purged and maintained with an inert atmosphere of nitrogen. This was followed by the addition of a solution of LiHMDS (1M, 27 mL, 5.0 equiv) in THF (31 mL) dropwise with stirring at −5° C. The resulting solution was stirred for 16 h at room temperature. The reaction was then quenched by the addition of ethanol (30 mL) and concentrated under vacuum. The residue was dissolved in EtOAc (300 mL) and washed with H₂O (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by silica gel chromatography (MeOH/CH₂Cl₂, 1:20) to afford 9-bromo-2,3,4,5-tetrahydro-6H-benzo[b][1,5]oxazocin-6-one as a red solid (300 mg, 21% yield). MS: (ES, m/z): 256 [M+H]⁺.

Step-5: 9-Bromo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine

9-Bromo-2,3,4,5-tetrahydro-6H-benzo[b][1,5]oxazocin-6-one (300 mg, 1.17 mmol, 1.0 equiv) and THF (10 mL) were placed in a 50-mL round-bottom flask. This was followed by the addition of a solution of borane-tetrahydrofuran complex (1M, 11.80 mL) dropwise with stirring at 0° C. The resulting solution was stirred for 16 h at 60° C. in an oil bath. The reaction was then cooled to 0° C. and quenched by the addition of MeOH (5 mL) at 0° C. Then 6M HCl (3 mL) was added. The resulting solution was stirred for 16 h at room temperature. Then the pH of the reaction was adjusted to 8 with aq. 4N NaOH. The resulting mixture was concentrated under vacuum. The residue was dissolved in EtOAc (100 mL) and washed with H₂O (3×30 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to afford 9-bromo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine as a light yellow solid (250 mg, 88% yield). MS: (ES, m/z): 242 [M+H]+.

Step-6: tert-Butyl 9-bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5(6H)-carboxylate

9-Bromo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine (140 mg, 0.58 mmol, 1.0 equiv), dichloromethane (5 mL), triethylamine (120 mg, 1.19 mmol, 2.0 equiv) and di-tert-butyl oxalate (260 mg, 1.29 mmol, 2.0 equiv) were placed in a 50-mL round-bottom flask. The resulting solution was stirred for 16 h at room temperature. The resulting mixture was concentrated and purified by silica gel chromatography (EtOAc/pet. ether, 1:3) to afford tert-butyl 9-bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5(6H)-carboxylate as a light yellow solid (130 mg, 66% yield). MS: (ES, m/z): 342 [M+H]⁺.

Step-7: 5-(tert-Butyl) 9-ethyl-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5,9(6H)-dicarboxylate

tert-Butyl 9-bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5(6H)-carboxylate (130 mg, 0.38 mmol, 1.0 equiv) in ethanol (10 mL), triethylamine (115 mg, 1.14 mmol, 3.0 equiv) and Pd(dppf)Cl₂.CH₂Cl₂ (27 mg, 0.04 mmol, 0.10 equiv) were placed in a 20-mL pressure tank reactor and CO(g) (50 atm) was introduced. The resulting mixture was stirred for 16 h at 120° C. in an oil bath and then concentrated under vacuum. The residue was dissolved in EtOAc (50 mL) and washed with H₂O (2×20 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by silica gel chromatography (EtOAc/pet. ether, 1:4) to afford 5-(tert-butyl) 9-ethyl-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5,9(6H)-dicarboxylate as light yellow oil (90 mg, 71% yield). MS: (ES, m/z): 336 [M+H]⁺.

Step-8: Ethyl 3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate

5-(tert-Butyl) 9-ethyl-3,4-dihydro-2H-benzo[b][1,5]oxazocine-5,9(6H)-dicarboxylate (90 mg, 0.27 mmol, 1.0 equiv) and dichloromethane (5 mL) were placed in a 50-mL round-bottom flask. This was followed by the addition of trifluoroacetic acid (5 mL) dropwise with stirring at 0° C. The resulting solution was stirred for 16 h at room temperature, then concentrated under vacuum. The residue was dissolved in H₂O (50 mL). The pH of the solution was adjusted to 8 with aq. 4N NaOH. The resulting solution was extracted with EtOAc (3×20 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to afford ethyl 3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate as light yellow oil (60 mg, 95% yield). MS: (ES, m/z): 236 [M+H]⁺.

Step-9: N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide

Ethyl 3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate (60 mg, 0.26 mmol, 1.0 equiv) and THF/MeOH (4:1, 1.5 mL) were placed in a 8-mL vial. Then solutions of hydroxylamine (50% in water, 0.51 mL, 30 equiv) and aq. 1M NaOH (0.51 mL, 2.0 equiv) were added at the same time. The resulting solution was stirred for 2 h at room temperature. The crude product was purified by Prep-HPLC (Column: XBridge BEH C18 OBD Prep 5 m 19×250 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: MeCN; Flow rate: 20 mL/min; Gradient: 2% B to 8% B in 6 min; Detector: UV 254, 220 nm). 1N HCl (0.26 mL, 1.0 equiv) was added to the product fractions and the mixture was lyophilized with 2N HCl (1 mL) to afford the hydrochloride salt of N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide as a off-white solid (23.7 mg, 36% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.35 (s, 1H), 9.42 (br s, 2H), 9.14 (br s, 1H), 7.61-7.54 (m, 3H), 4.17-4.15 (t, J=4.8 Hz, 4H), 3.13 (s, 2H), 1.82 (s, 2H). MS: (ES, m/z): 223 [M−HCl+H]⁺.

Example 2—Preparation of N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide

Step-1: 9-Bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocin-5(6H)-yl)(tetrahydro-2H-pyran-4-yl)methanone

9-Bromo-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine (250 mg, 1.03 mmol, 1.0 equiv) and DMF (3 mL) were placed in a 25-mL round-bottom flask. This was followed by the addition of oxane-4-carboxylic acid (162 mg, 1.24 mmol, 1.2 equiv), HATU (471 mg, 1.95 mmol, 1.2 equiv) and DIEA (402 mg, 3.11 mmol, 3.0 equiv) at 0° C. The resulting solution was stirred for 16 h at room temperature. The resulting solution was diluted with EtOAc (15 mL) and washed with H₂O (5×50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, concentrated, and purified by silica gel chromatography (MeOH/CH₂Cl₂, 1:25) to afford 9-bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocin-5(6H)-yl)(tetrahydro-2H-pyran-4-yl)methanone as light yellow oil (200 mg, 55% yield). MS: (ES, m/z): 354 [M+H]⁺.

Step-2: Ethyl 5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate

9-Bromo-3,4-dihydro-2H-benzo[b][1,5]oxazocin-5(6H)-yl)(tetrahydro-2H-pyran-4-yl)methanone (170 mg, 0.48 mmol, 1.0 equiv) in EtOH (15 mL), triethylamine (242 mg, 2.39 mmol, 3.0 equiv) and Pd(dppf)Cl₂.CH₂Cl₂ (36 mg, 0.05 mmol, 0.10 equiv) were place in a 20-mL pressure tank reactor and CO(g) (50 atm) was introduced. The resulting mixture was stirred for 16 h at 120° C. in an oil bath. The resulting mixture was concentrated and purified by silica gel chromatography (MeOH/CH₂Cl₂, 1:25) to afford ethyl 5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate as light brown oil (160 mg, 96% yield). MS: (ES, m/z): 348 [M+H]⁺.

Step-3: N-Hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide

Ethyl 5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxylate (85 mg, 0.24 mmol, 1.0 equiv) and THF/MeOH (4:1, 1.5 mL) were placed in a 8-mL vial. Then solutions of hydroxylamine (50% in water, 0.48 mL, 30 equiv) and aq. 1N NaOH (0.49 mL, 2.0 equiv) were added at the same time. The resulting solution was stirred for 2 h at room temperature. The crude product was purified by Prep-HPLC (Column: XBridge C18 OBD Prep 5 m 19×150 mm; Mobile Phase A: Water/0.1% Formic Acid; Mobile Phase B: MeCN; Flow rate: 25 mL/min; Gradient: 5% B to 43% B in 7 min; Detector: UV 254, 220 nm) to afford N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide as a pink solid (12.7 mg, 16% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.10 (br s, 1H), 9.05 (br s, 1H), 7.53-7.39 (m, 3H), 4.71-4.48 (d, 2H), 4.16-4.03 (m, 2H), 3.82-3.67 (m, 4H), 3.37-3.30 (m, 2H), 3.00-2.76 (m, 1H), 1.76-1.72 (m, 2H), 1.61-1.25 (m, 4H). MS: (ES, m/z): 335 [M+H]⁺.

TABLE 1 The following compound was prepared by the method of Example 2. Found Structure M + H ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm)

(ES, m/z): 349 [M + H]⁺ 11.16 (br s, 1H), 9.05 (br s, 1H), 7.49-7.44 (m, 3H), 4.56 (s, 2H), 4.17-4.14 (t, J = 5.6 Hz, 2H), 3.82-3.80 (t, J = 4 Hz, 2H), 3.60-3.55 (m, 2H), 3.40-3.36 (t J = 8.8 Hz, 2H), 1.97-1.94 (d, J = 14.4 Hz, 2H), 1.65 (s, 2H), 1.46-1.40 (m, 2H), 1.22 (s, 3H).

Example 3—In Vitro Histone Deacetylase Assay

The enzymatic HDAC6 assay was performed using electrophoretic mobility shift assay. Full length human recombinant HDAC6 protein were expressed in baculoviral system and purified by affinity chromatography. The enzymatic reactions were assembled in 384 well plates in a total volume of 25 μL in a reaction buffer composing: 100 mM HEPES, pH7.5, 25 mM KCl, 0.1% bovine serum albumin, 0.01% Triton X-100, 1% DMSO (from compounds) 2 μM of the fluorescently labeled peptide substrate and enzyme. The enzyme was added at a final concentration of 1 nM. The peptide substrate RHKK(Ac)—NH2 was used. The compounds were tested at 12 concentrations spaced by 3× dilution intervals. Negative control samples (0%-inhibition in the absence of inhibitor) and positive control samples (100%-inhibition) were assembled in replicates of four in each assay plate. The reactions were incubated at 25° C. and quenched by the addition of 45 μL of termination buffer (100 mM HEPES, pH 7.5, 0.01% Triton X-100, 0.05% SDS).

The terminated assay plates were analyzed on LabChip® 3000 microfluidic electrophoresis instrument (Perkin Elmer/Caliper Life Sciences). The fluorescence intensity of the electrophoretically separated de-acetylated product and substrate peptide were measured. Activity in each sample was determined as the product to sum ratio (PSR): P/(S+P), where P is the peak height of the product peptide and S is the peak height of the substrate peptide. Percent inhibition (Pinh) was determined using the following equation:

Pinh=(PSRO %−PSRinh)/(PSRO %−PSR100%)*100, where PSRinh is the product sum ratio in the presence of inhibitor, PSRO % is the average product sum ration in the absence of inhibitor and PSR100% is the average product sum ratio in 100%-inhibition control samples. The IC50 values of inhibitors are determined by fitting the %-inhibition curves with 4 parameter dose-response model using XLfit 4 software.

As set forth in Table 2, below, IC₅₀ values are defined as follows: IC50≤0.1 μM (+++); IC50>0.1 μM and ≤0.5 μM (++); IC50>0.5 μM (+).

TABLE 2 Inhibitory Concentration (IC50) Values for Representative Compounds against HDAC6. Activity NAME Range N-hydroxy-3,4,5,6-tetrahydro-2H-benzo[b][1,5]oxazocine-9- + carboxamide N-hydroxy-5-(tetrahydro-2H-pyran-4-carbonyl)-3,4,5,6- ++ tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide N-hydroxy-5-(4-methyltetrahydro-2H-pyran-4-carbonyl)-3,4,5,6- +++ tetrahydro-2H-benzo[b][1,5]oxazocine-9-carboxamide

EQUIVALENTS

While the present invention has been described in conjunction with the specific embodiments set forth above, many alternatives, modifications and other variations thereof will be apparent to those of ordinary skill in the art. All such alternatives, modifications and variations are intended to fall within the spirit and scope of the present invention. 

The invention claimed is:
 1. A compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein: X¹ is CR¹R²; X² is NR³; X³, X⁴, and X⁵ are each CR¹R²; Y¹ and Y⁴ are each independently N or CR¹; Y² and Y³ are each independently N or CR¹ when not bonded to C(O)NHOH and Y² and Y³ are C when bonded to C(O)NHOH; L is a bond, —(CR¹R²)_(n)—, —C(O)—, —C(O)O—, —C(O)NR³—, —S(O)₂—, —S(O)₂NR³—, —S(O)—, —S(O)NR³—, —C(O)(CR¹R²)_(n)O—, or —C(O)(CR¹R²)_(n)—; R is independently, and at each occurrence, —H, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, —C₅-C₁₂spirocyclyl, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1-5 heteroatoms selected from N, S, P, or O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocyclyl, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocyclyl, aryl, and heteroaryl, with the proviso that when L is —C(O)— the spiroheterocyclyl is not bound to L via a nitrogen atom; R¹ and R² are independently, and at each occurrence, —H, R³, R⁴, —C₁-C₆alkyl, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from N, S, P, or O, —OH, halogen, —NO₂, —CN, —N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)₂R⁵, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, or (CHR⁵)—NR³R⁴, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —OR³, —NHR³, —NR³R⁴, —S(O)₂N(R³)₂, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from N, S, P, or O; R³ and R⁴ are independently, and at each occurrence, —H, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from N, S, P, or O, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂(C₁-C₆alkyl), —(C₁-C₆alkyl)S(O)₂R⁵, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, and —(CHR⁵)_(n)N(C₁-C₆alkyl)₂, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —O(C₁-C₆)alkyl, —NH(C₁-C₆)alkyl, —N(C₁-C₆alkyl)₂, —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂NHC₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)S(O)₂C₁-C₆alkyl, —S(O)R⁵, —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)R⁵, heterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from N, S, P, or O; R⁵ is independently, and at each occurrence, —H, —C₂-C₆alkenyl, —C₄-C₈cycloalkenyl, —C₂-C₆alkynyl, —C₃-C₈cycloalkyl, heterocyclyl, aryl, heteroaryl, —OH, halogen, —NO₂, —CN, —N(C₁-C₆alkyl)₂, —S(O)₂NH(C₁-C₆alkyl), —S(O)₂N(C₁-C₆alkyl)₂, —S(O)₂C₁-C₆alkyl, —C(O)C₁-C₆alkyl, —CO₂C₁-C₆alkyl, —N(C₁-C₆alkyl)SO₂C₁-C₆alkyl, —S(O)(C₁-C₆alkyl), —S(O)N(C₁-C₆alkyl)₂, —N(C₁-C₆alkyl)S(O)(C₁-C₆alkyl), or (CH₂)_(n)N(C₁-C₆alkyl)₂; and n is independently, and at each occurrence, an integer from 0 to
 6. 2. The compound of claim 1, wherein X¹, X³, X⁴, and X⁵ are each CH₂.
 3. The compound of claim 1, wherein the compound is of the Formula IA:

or a pharmaceutically acceptable salt thereof.
 4. The compound of claim 1, wherein the compound is of the Formula IB:

or a pharmaceutically acceptable salt thereof.
 5. The compound of claim 1 selected from: N-hydroxy-5-methyl-2-phenyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 2-benzyl-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 2-benzoyl-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 2-(cyclohexanecarbonyl)-N-hydroxy-5-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; N-hydroxy-5-methyl-2-(tetrahydro-2H-pyran-4-carbonyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; N8-hydroxy-5-methyl-N2-phenyl-3,4,5,6-tetrahydrobenzo[f][1,4]diazocine-2,8(1H)-dicarboxamide; N-hydroxy-5-methyl-2-(N-phenylsulfamoyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; N-hydroxy-2-methyl-5-phenyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 5-benzyl-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 5-benzoyl-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; 5-(cyclohexanecarbonyl)-N-hydroxy-2-methyl-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; N-hydroxy-2-methyl-5-(tetrahydro-2H-pyran-4-carbonyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide; N9-hydroxy-5-methyl-N2-phenyl-3,4,5,6-tetrahydrobenzo[f][1,4]diazocine-2,9(1H)-dicarboxamide; or N-hydroxy-2-methyl-5-(N-phenylsulfamoyl)-1,2,3,4,5,6-hexahydrobenzo[f][1,4]diazocine-8-carboxamide.
 6. A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.
 7. The compound of claim 1, wherein Y¹, Y³, and Y⁴ are each CR¹ and Y² is C.
 8. The compound of claim 1, wherein Y¹, Y², and Y⁴ are each CR¹ and Y³ is C.
 9. The compound of claim 1, wherein X² is N(CH₃).
 10. The compound of claim 9, wherein R is —C₃-C₈cycloalkyl, heterocyclyl, or aryl.
 11. The compound of claim 10, wherein R is aryl.
 12. The compound of claim 10, wherein R is heterocyclyl.
 13. The compound of claim 10, wherein R is —C₃-C₈cycloalkyl.
 14. The compound of claim 10, wherein L is a bond, —CH₂—, —C(O)—, —C(O)NH—, or —S(O)₂NH—.
 15. The compound of claim 14, wherein L is a bond.
 16. The compound of claim 14, wherein L is —CH₂—.
 17. The compound of claim 14, wherein L is —C(O)—.
 18. The compound of claim 14, wherein L is —C(O)NH—.
 19. The compound of claim 14, wherein L is —S(O)₂NH—. 